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Topic: Top 10 mods for Mini lathe please ? (Read 14314 times)

Hi all I hope this is the right place to post this if not please advise.

I have just bought a used mini lathe Axminster type sc2.. And it's my first lathe. With that in mind I would like to get this machine to the Best it can do. Ironically the chap that owned it was an engineer ...umm not sure about that..bolts loose no adjustments made still sand in components etc. Anyway I have to put it right and sort it out. If anyone has done a lot of mods on these and worked out the ones that really make the difference I would love to know what and how. Here's hoping for a nice Christmas list ! God I hope it's max 10 !

I have a chester 8", a bit bigger but same family. What I have done, roughly in order. -- Strip and clean, take out gib strips and clean up with fine file and/or emery paper. This made a big difference, not yet fitted brass gibs. Drill and tap ( M6) 4 holes in cross slide, for fitting angle plate, etc. Fit a hand wheel to end of the leadscrew. Make an expanding mandrel for outer end of spindle, mostly for a handle for screwcutting but also to fit a gear wheel for indexing. This is just basic no-cost stuff but does make difference.

Buell -- #1) Line up and "fix" your tailstock (tapered) bore to be concentric and aligned your spindle. #2) Change your tailstock over to a "cam-lock" clamp to your bed. #3) QCTP. Others will occur to you as things progress, but this is (from my view of the universe) the places to begin. In terms of item #1, my spindle was out of concentricity by (nearly) .015 in and out of alignment by (about) .005/inch of tail bore travel. In terms of item #2, I cannot tell you how much time is saved each day because I do not have to "find" the wrench to tighten things. In terms of item #3, think about it...

Hi Buell, There is a wealth of information in the Yahoo Group for the 7x12 Mini Lathe user group. see betagroups.yahoo.com I joined the group several years ago and have made a number of mods to my lathe.

I can see I'm going to enjoy this Forum...lots of good ideas from Guys that Know this machine very well...ummm looks like I'm gonna get to know it intimately.

I have rebuilt bike engines..car engines all to an acceptable level but the tolerances on this in order for it to perform correctly ....well they have to be spot on ! Go slow with me guys ! Thanks for all the ideas already !

Buell -- #1) Line up and "fix" your tailstock (tapered) bore to be concentric and aligned your spindle.

Sorry not great with the terminology ... My dyslexic ness in basic terms.. Make sure the two centres are in line with each other ? Being tail stock and centre of the chuck ? Tapered to concentric what's that about ? Any link would be Fabtastic . Thanks again

I have a somewhat older version of the mini lathe from Einhell. The two important mods I did were to replace the ball races in the headstock with taper roller bearings and to remachine the tailstock base to remove the play. I think that it is referred to here:

I've had a Sieg C3 for over 10 years. This is what I've changed, more or less in order of importance or effectiveness...1/ Change spindle bearings to taper roller bearings2/ Change carriage gibs from the waste of space originals to taper gibs3/ Make a REALLY rigid post and clamp-on style QCTP4/ Change cross and compound slide gibs to brass 5/ My original drip tray and chip shield were painted black, awful light sucking finish. I cleaned, rubbed them down and repainted them white, vast improvement!!6/ Made a more effective half nut retaining strip, from flat bar, rather than the original two washers

I have the slightly bigger Sieg C3, the super model with brushless motor...

I have added a qctp to mine (Arceurotrade sell a suitable one)

I changed the gibs from the rough steel ones to nice shiny brass ones.Same for the saddle retainers...

I have made an extra crosslide from a billet if cast iron with tee slots across for holding stuff....

Changed the plasticy handwheels and gears for more blingy polished ally ones...

Mine has the camlock for the tails stock, but I converted an early C3 tailstock to the same design..easy peasy...

Made a saddle lock that utilises the holes for the trav steady.

This is the list! I've done the same ones as above with the exception of the extra cross slide. One thing to mention is that whenever you do something plan ahead so you do any lathe work before you dismantle your lathe... DAMHIKT...

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Henning

Just because i can't, doesn't mean i shouldn't? Tool- lover, with a collection to show for it!

This is the list! I've done the same ones as above with the exception of the extra cross slide. One thing to mention is that whenever you do something plan ahead so you do any lathe work before you dismantle your lathe... DAMHIKT...

Great now you tell me that. Does that mean I can buy a Milling machine ! I have the smallest workshop known to mankind.....oh sod it will build a bigger workshop as well as fixing the lathe ! This addiction is getting worse being on this Forum.....where's the Help page !

This is the list! I've done the same ones as above with the exception of the extra cross slide. One thing to mention is that whenever you do something plan ahead so you do any lathe work before you dismantle your lathe... DAMHIKT...

Great now you tell me that. Does that mean I can buy a Milling machine ! I have the smallest workshop known to mankind.....oh sod it will build a bigger workshop as well as fixing the lathe ! This addiction is getting worse being on this Forum.....where's the Help page !

Well, in my defense I told you as soon as I saw your post

The small workshop syndrome will never disappear either I'm afraid. I've doubled the size of mine and it's still waaaay too small.

There's a toolhoarders anonymous around here somewhere for help and I believe there's a branch of a couple others as well, like "rather be in the workshop dreaming up stuff I have no room to build group" and also the "if I only had (insert tool here)- group".Not really sure any of those will do you any good though... hasn't worked for me.My trailer is firmly attached to the car awaiting picking up of what I believe to be a rather nice wood turning lathe later today and if all goes well I'll have an Emco unimat 3 as well will go great with my V10P.

SWMBO usually tell people that I'm not interested in tools. She upholds it's a genetical disorder...

Logged

Henning

Just because i can't, doesn't mean i shouldn't? Tool- lover, with a collection to show for it!

My wife was complementing me, because now there is a clear path cross the room in the garage and on one bedroom that is coming my clean "metrology lab". They still have too much stuff but I'm getting control over it slowly.

Lew's document was interesting...I think I could follow intent and procedure pretty well. Only in the end it was a little unclear how the tail stock part was installed over the alignment rod. I think that one peg on the steady rest is made loose and rod has been removed from the chucked weldon holder, then the tail stock upper part dropped into it's place (on epoxy) and finally the rod pushed trough, tightened and collets put finaly to allign the tail stock?

What ever you do. Don't use the lathe parts to "lap" ways. It looks fine, feels fine and is all wrong.

Best thing I did was get divorced...I remember her saying every time I came home from work " Your not leaving those tools in the hallway are you ?" My reply was the same every time .." When you start paying the mortgage and your names on the mortgage I will take them out " I now live in a 3 bed place and One of the bedrooms is converted to a leather working studio !....at this rate the other 2 will be a Machinery shop !

Lew's document was interesting...I think I could follow intent and procedure pretty well. Only in the end it was a little unclear how the tail stock part was installed over the alignment rod. I think that one peg on the steady rest is made loose and rod has been removed from the chucked weldon holder, then the tail stock upper part dropped into it's place (on epoxy) and finally the rod pushed trough, tightened and collets put finaly to allign the tail stock?

Essentially, yes. The main difference is that I used my (vertical height) indicator set-up to verify that my rod was not deformed as the tailstock and epoxy stack-up was aligned. My tailstock and chuck/collet now align within .0001 inch TIR.

I will likely fit the 7x with spare small ac servos, 60V, as I have a set of 10.And a pokeys ethernet controller, good for 125 kHz.Another idea is machining a new 7-8x minilathe from scratch.As a technology demonstrator, probably circa 100 kg in mass.

Quick change tool-postArc Eurotrade brass gibs for top and cross slides.Better gibs for saddle (my own design)Ball-race bearings for top and cross slide lead-screws (gets rid of most of the backlash and feels really smooth)Longer cross-slide lead-screw for longer slide travelShim lead-screw nuts (eliminates the horrid three-screw, never right, loosens twice a week arrangent - turns head and spits)Lever lock for tailstockEmco T-slot plate bolted to cross-slide (to fit vertical slide for small milling jobs)Handle for headstockDividing head arrangement for headstock (mostly used for marking out)Taper bearings for headstock

Step 1.. Tapered bearings...Any preference...Fag...Skf..Timken etc ? Do I have to modify anything else as dimension slightly different ?

Eat Xmas dinner

Step 1..... Buy decent taper rollers.....no preference from your chosen names...You will need to polish the journals where the orig bearings sat on the shaft....If you remember the bearings were tight on the shaft and the casting....( werent they?) the new bearing inner races need to slide on the spindle journals to achieve correct preload....so polish the journals with some fine emery until the inner races are a tight push fit....dont take off too much, remember you only need to polish them....The spacers on the shaft will need replacing, the new bearings are a different thickness to the old ones. I used some 6086 ally bar, plastic is no good for taper bearing preload, material stability....

Rework so far should have you ready to reassemble the headstock...by the way, it might pay you to get metal gears instead of the plastic ones.....( something often overlooked in a rebuild like this)

Appreciate those answers.. Didn't think about the external plastic covers being plastic ! Ahh..whats the deal with the changing over to metal gears ? I have heard The noise factor...The fact that something than give rather than it all being rigid in the drive chain. also am i right in thinking that although you change the main Gears for steel the smaller ones still end up being plastic ? so in all that you still have some Plastic ? or you can replace all ?

Nachi tapered roller bearings have been reputed (in a letter years ago, on the Arc Euro site?) to be excellent. I don't know of any information comparing these with the other brands you mention, though.

Gone with the Skf as these are the ones on My bike and have had no Bother with them in 6 years headstock.

I'm looking at the headstock today and I'm understanding the design of it...

So new taper bearings go in and the exact position of where they end up on the craft is determined by the plastic spacers that are fitted at the end of the shaft ? Reason I ask is obviously to understand, but the Journal (if that's the right word) that both bearings are positioned on are some 2mm+ than the bearing. So dependant on thickness of the spacer /s before the two locking nuts....determines exactly how much of the shaft is sticking out toward the chuck ? Or Am I missing something simple.